1. Field of the Invention
The present invention relates to a multi-cylinder compressor provided with plural gas compression parts, and especially to the one enabled to increase an intake gas quantity.
2. Detailed Description of the Prior Art
Conventionally, a multi-cylinder compressor, which is arranged so as to discharge a high-pressure gas by compressing an intake gas through plural gas compression parts, has been known. For example, as shown in FIG. 7, a 4-cylinder compressor has been known, wherein four gas compression parts A, B, C, D are arranged crosswise and opposite to each other. In the 4-cylinder compressor, the intake gas is compressed by the 1st gas compression part A and sent to the next gas compression part B, and the gas is compressed by the gas compression part B and then is sent to the next gas compression part C, and further compressed by the gas compression part C before it is sent to the next gas compression part D, and finally compressed by the gas compression part D and discharged. Namely, the intake gas is sequentially compressed by the gas compression parts A through D, and is discharged as a high-pressure gas.
In this case, in order to discharge a gas at 30 MPa as a final high pressure, normally, a gas of 0-0.05 MPa is raised step by step by each gas compression part A-D with a compression ratio of 3-5. The later the stage is, the smaller cylinder diameter of the gas compression parts A-D have, and this is called a 4-cylinder 4-stage compressor. However, it has been found out from experiments that if the 1st intake gas is pressurized up to 0.5 Mpa, the 1st stage gas compression part A is not necessary, namely, the final gas pressure of 30 Mpa can be obtained experimentally from a 3-cylinder 3-stage compressor consisting of the 2nd gas compression part B, the 3rd gas compression part C, and the 4th gas compression part D.
The 3-cylinder 3-stage compressor is arranged just like the 4-cylinder 4-stage compressor as shown in FIG. 8 so that a gas is sucked from the intake port H arranged on the bearing plate G located on the top of a housing F of the compressor main body, and the gas is sucked into the 2nd stage gas compression part B for compression thereof.